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Nov. 9 1926.

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W. W. CARPENTER TELEPHONE EXCHANGE SYSTEM Original Filed Oct. 2, 1923 s Sheets-Sheet s l atented Nov. 9, 1925.

barren srarss LthSfiZlt PATENT @FHQE.

WARE-EN W. CARPENTER, OF QUEENS, NEW YORK, ASSIGNOR 'lO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM. 7

Application filed October 2, 1923, Serial No. 666,159. Renewed. April 5, 1926.

This invention relates to telephone exchange systems and particularly to systems wherein automatic switching apparatus is employed for the purpose of establishing conversational connections. v p

T he object of the invention is an improved organization of recording and controlling mechanism for governing the selective action of automatic switches.

A feature of the inventionrelates to the provision, in a system employing switches of the progressively operable type, of recording devices which receive designation records and controlling mechanisms common to said devices and cooperating therewith to directively control the operation of the switches.

Other and further features contemplated by this invention will be more clearly understood from the following detailed description and also from the appended claims.

Referring to the drawings, Figs. 1 to 6, inclusive, when arranged in the order illus trated in Fig. 7, disclose-a sufficient portion of a telephone exchange system wherein the features of the invention are incorporated to enable a thorough understanding thereof.

'Fig. 1 diagrammatically illustrates a line switch of the coordinate type in which the subscribers lines terminate, one of a number of trunks outgoing to a first selector switch of the step-bystep type. and cooperating with said trunks a sender selector switch.

Fig. 2 shows this step-by-step first selector switch associated with the trunk shown in Fig. 1 and also diagrammatically a succeeding connector switch of the step-by-step type having a control relay 290 and operating magnets 291 and 292 and a subscribers line. v

Figs. 3 and 4 show one of a number of common register senders that-may be associated with the outgoing trunks by means of the sends selector switch shown in Fig. 1. F: g. 3 illustrates the impulse receiving mechanism, including a set of counting relays and Fig. 4 shows three numerical relay registers.

In the lower'partof Fig. 5 is disclosed a sender connector switch for connecting the register sender to a marker equipment.

The remainder of Fig. 5 and Fig. 6 illustrate this marker or selection controlling mechanism which is common to a plurality of first selector switches and the associated trunks leading to a plurality of groups of connectors.

General description of the system and apparows.

The telephone system herein disclosed employs an improved method of controlling switches. The line switch 100 and sender selector switch 130 may be of any suitable type such as coordinate or cross-bar switches. The. sender connector switch 500, the marker switch 600, hereinafter. called a frame connector and the marker. switch 650, hereinafter called a runk connector. are of the relay type. The first selector switch 200 and the connector switch 250 are of the stepby-step type. These switches serve to establish connections between incoming lines or circuits such as 101, and outgoing lines or circuits such as 201. v

A number of subscribers lines such as 101 are'shown entering an exchange and ap pear as calling lines in a coordinate line switch such as 100. These line switches are provided with a number of outgoing trunks such as.103 and each of these trunks has an appearance in a sender selector such as 130, for the association of said trunks with any one of a number of register senders such as the sender 300 shown in Figs. 8 and 4.

Each of these trunks outgoing from the line switch also appears as an incoming trunk in a step-by-step first selector switch having a vertical and rotary movement. Trunk 103 is shown in Fig. 2 connected to the first selector switch 200 having access to a plurality of groups of trunks having their terminals arranged in horizontal rows, three trunks of the first horizontal row only being shown. Each group of trunks may be connected to connector switches of the step-by-step type and the third trunk in the first group is shown connected to aswitch 250 indicated diagrammatically and having access to a number of subscribers lines such There being a plurality of register senders such as 800 sender connectors such as 500 are provided to connect different senders to the marker equipments. In the particular register sender 300 there is provided besides the counting relays shown in Fig. 3 a series of relay registers 400, 402 and 403 for the registration of hundreds, tens and units digits respectively. In the common sender connector 500, the connection from the hundreds relay register 400 only is shown. In the marker only the corresponding hundreds digit relays 520, 521, 522 and 526 connected by means of this sender connector to this relay register are shown. Although not shown, it is understood that the tens and units relay registers'402 and 403 may be similarly connected with their correspond ing tens and units relays in the marker by means of this common sender connector 500.

In Fig. 6 is shown a frame connector 600 with the circuit arrangements necessary for the association of the first selector switch 200 with the hundreds digit relays to cause the said switchto be advanced to the proper group of trunks, and a trunk connector 650 with the corresponding trunk testing relays 660 having similar circuit arrangements to cause the trunks in the selected group of trunks to be tested. The circuits for testing three trunks in the first group only are shown. The start relay 601 is the relay arranged to start this particular marker equipment to operate the first selector 200, and the group relay 602 is arranged to plck out the first group of trunks for testing. The countin relays 510 shown in Fig. 5 are associated with this equipment for the control of the above operations.

' It is readily seen that the frame connector 600 may be equipped and operated so as to connect any other marker in a similar manner, and the trunk connector 650 so as to connect any other grou s of trunks depending on the hundreds igits selected by the calling subscriber.

For performing succeeding groups selections as well as the tens and units selection beyond the first selector similar marker equipments may be rovided for this purpose and initiation 0 such selections will be touched upon in the following detailed description of the operation of the circuit arran ement shown.

The structure of the coordinate switches includes briefly a. number of vertical oper atin bars which control contacts of incoming and outgoing lines and a number of horizontal operating bars which control contacts of the link circuits. The conjoined operation of two vertical bars and a horizontal bar causes the establishment of a connection. For a complete description of a structure of this character reference may be had to the patent to C. L. Goodrum and J. N. Reynolds, No. 1,515,735, granted November 18, 1924, and to the patent to S. B. Williams, No. 1,517,331, granted Decemher 2, 1924.

The first selector switch 200 and the connector switch 210 being of the step-by-step type ma be of the general character known as the trowger switches in which brushes are 0 erated in a primary vertical direction to se eat a horizontal row of terminals and a secondary rotary direction to hunt or select a set of terminals in the vertical row selected by the primary movement.

Detailed description of establishment of a connection.

Consider that the subscriber of line 101 desires to hold a conversation with the subscriber on line 201 appearing in the same central office. It may also be assumed that the directory number of the subscribersline 201 is 134. The initiation of the call on the calling subscribers line causes the operation of the line switch 100 whereby the line is extended over an idle link 115 to idle trunk 103 extending to the first selector switch 200. Furthermore, the initiation of the call causes the operation of the sender selector switch 130 and the calling subscribers line is extended over the link circuit 132 and the circuit 134 to the idle register sender 300 shown in Figs. 3 and 4. Had the sender illustrated been busy, the subscribers line would be extended over another circuit such as the circuit 135 leading to another sender, not shown. For an understanding of the manner in which calling lines are extended to idle trunks, and to idle senders, through line switches and sender selectors of the co ordinate type, reference is made to the patent to S. B. WVilliams, No. 1,517,331, granted December 2, 1924. During the op eration of the sender selector switch 130, a circuit may be closed in any suitable manner for the relay 105. Relay 105 operates and closes a circuit from battery through the winding of slow-to-relea-se relay 107, to ground at the inner left contact of relay 105. Relay 107 places ground on the sleeve conductor 116 of the trunk 103. Relay 105 in operating, extends the tip and ring condoctors of the trunk 103 through the sender selector 130 to the register sender mechanism 300. An impulse circuit is thereupon completed as follows: battery, through the resistance 318, winding of impulse relay 301, outer left contact of relay 303, conductor 319 through contacts of the sender selector switch 130, conductor 138, inner right contact of relay 105 thence over the ring conductor of trunk 103 through contacts of the line switch 100 over the subscribers line and returning over the tip conductor through the line switch 100, outer right contact of relay 105, conductor 139, through contacts of the sender selector switch 130, conductor 320, inner left contact of relay 303, winding of the balancing coil 302, to ground. The impulse relay 301 operates and closes a circuit for the slowto-release relay 304. Relay 304 completes a circuit from ground through its left contact, conductors 321, 322 through contacts of the switch 130, conductor 140, winding of relay 105 to battery. Relay 105 is held in this circuit under the control of the relay 304 in the sender. pletes the circuit from ground through its left contact over conductor 321, left contact of relay 305, left back contact of relay 306, winding of slow-to-release relay 307 to battery. Relay 307 operates in this circuit.

The apparatus is now in condition for receiving the first series of impulses. The calling subscriber manipulates his impulse transmitter to send the first series, in the present case consisting of a single impulse. At the time the relay 304 operates, it closes a circuit from battery, resistance 339, through the left hand winding of relay 308 to ground at the right hand contact of said relay 304. Relay 308, however, does not operate since it is shunted by the following path: battery, resistance 339, through the right contact of relay 301 to ground at the right contact of relay 304. In response to the first impulse, relay 301 releases and opens the shunt around the left hand winding of relay 308 and this latter relay operates. Relay 308 closes a circuit from battery through the winding of relay 306, outer left contact of relay 308 to ground over conductor 321. Relay 306 operates and locks in a circuit through its left front contact, left contact of relay 305, to the grounded conductor 321. Relay 306 opens the original circuit of relay 307. The latter relay now is energized in a circuit traceable through the outer right contact of relay 308 to ground over conductor 321.

Relay 308 closes a circuit through the left hand winding of relay 309 to ground at the inner left contact of relay 308. Relay 309 operates and closes a circuit from battery through its right hand winding and inner right contact to the grounded conductor 321. Relay 309 in operating, completes a circuit through its left hand winding and left contact, conductor 324, outer right back contacts of counting relays 315, 314, 313 and 312 in series, winding of relay 312, outer left back contact of relay 313, conductors 325 and 326, outer right contact of relay .305, left front contact of relay 306, left contact of relay 305 to ground over conductor 321. So long as the relay 308 remains operated, however, relay 312 is shunted and does not receive sufficient current in the circuit traced to operate. At the end of the impulse, the subscribers line is closed, relay 301 operates and shunts relay 308 and this latter relay releases, opening the original circuit through the left hand winding of relay 309. Relay 312 now operates in series with the left hand winding of relay 309. Relay 312 looks in a circuit, from battery over conductor 327, inner right contact of relay 312, winding of said relay,

Relay 304 also com left back contact of relay 313 to ground over conductor 325.

It should be noted at this point that the armatures of the counting relay 312, and this is true of the remaining counting relays, are so arranged that the inner right contact is closed slightly in advance of the opening of the outer right back contact. By this arrangement, the locking of the relay is sure to occur before the energizing circuit is opened.

Immediately that the relay 312 opens its back contact the circuit through the left hand winding of relay 309 is opened. Relay 309 is wound differentially and hence when the left hand winding is opened, the effect of the right hand winding is to cause a quicker release. The right hand winding of relay 309 although differential to the left hand winding is not strong enough to cause the release of the relay when the left hand winding is fully energized. lVhen the inner right armature of the counting relay engages its front contact, a shunt is placed around the left winding of relay 309 which momentarily reduces the current in said winding. An instant later, the outer right back contact of the counting relay is opened, thus opening the circuit through the left winding of relay 309. The flux set up by the left winding of the relay 309 having thus been reduced, the effect of the differential right hand winding is to cause a quick release thereof. After an interval has elapsed following the impulse series, the slow-to-release relay 307 retracts its armature. A circuit now leads from ground over conductor 321, contact of relay 307, right contact of relay 306, inner right contact of relay 305, conductor 328, right back contact of relay 408, winding of relay 407 to battery. Relay 407 operates and connects the control leads from the counting relays through to the hundreds register 400. Relay 407 also completes a circuit from battery through its winding and inner upper contact, conductor 426, winding 1 of relay 305, right contact of relays 306 and 307 to the grounded conductor 321. Relay 305 does not operate at this time since its winding is shunted by the path previously traced through the winding of relay 407.

lVith relay 407 operated and the first count ing relay 312 energized, a circuit is closed from ground over conductor 326, conductor 325, outer left front contact of relay 312, conductor 329, outer right back contact of relay 317, conductor 330, lowermost contact of relay 407, winding of relay 404 to battery. A branch circuit also extends by way of conductor 427 through the winding of relay 423 to battery. Relays 404 and 423 operate and lock in a circuit traceable through the inner left contact of relay 404, conductor 428 to the holding conductor 321.

Relay 404 completes a circuit from battery through the winding of relay 408 to the grounded conductor 428. Relay 408 operates and locks through its inner left contact. Relay 408 opens the shunt around the winding of relay and this latter relay operates in series with relay 407. Relay 305 opens the holding circuit of relay 306 and relay 306 releases to in turn open the circuit of relays 305 and 407. Relay 407 releases and disconnects the control leads from the registers. Relay 305 in operating removes ground potential from conductor 326 to permit the release of all energized counting relays.

The subscriber next transmits the second series consisting of three impulses representing the second digit of the wanted number. The first two impulses cause the operation of counting relays 312 and and the release of relay 312. Upon the transmission of the third impulse, a circuit is completed through the left hand winding of relay 309 over conductor 324 through the outer right back contacts of relays 315 and 314, outer right front contact of relay 313, winding of relay 314, outer left back contact of relay 315, to ground over conductor 325. Relay 314 operates and locks through its inner right contact and Winding and through the outer left contact of relay 315 to the grounded conductor 325. Relay 314 opens the circuit of relay 313. Relay 314 also opens the circuit of the left hand winding of relay 309 and this relay being wound differentially releases immediately. After the elapse of a given interval following the third impulse, the slow relay 307 becomes deenergized and the circuit hereiubefore traced is closed by way of conductor 328 through the right front contacts of relay 408, right back contact of relay 416, winding of relay 415 to battery. Relay 415 operates extending the control leads from the counting relays througl'i to the tens register 402 and also closing a circuit to battery through its winding and inner upper contact over conductors 430 and 426 through the winding of relay 305 as traced to ground. Relay 305 being shunted remains inert until relay 416 is operated.

lVith relay 415 and third counting relay 314 operated, a circuit may be traced from ground over conductors 320 and 325 through the outer left front contact of relay 314, conductor 330, lower contact of relay 415, winding of relay 413 to battery and another circuit from ground over conductor 326,

' through the inner left contact of relay 314,

conductor 331, next to the lower contact of relay 415, winding of relay 414 to battery. Relays 413 and 414 operate and lock in circuits from battery through the windings and inner left contacts to ground over conductors 432 and 321. Relay 413 closes a circuit fiom battery through the winding of relay 416, outer left contact of relay 413, to the grounded conductor 432. Relay 416 looks in a. circuit through its Winding and left contact to the grounded conductor 321. Relay 416 opens the shunt around the Winding of relay 305 and this latter relay operates in series with relay 415. Relay 305 in the manner already explained opens the circuit of relay 306 whereupon relays 305 and 415 are deenergized and the sender is placed in condition for receiving the last series of impulses.

The calling subscriber sends the last se ries of four impulses in response to the first three of which relays 312, 313 and 314 are operated in succession and relays 312 and 313 are released in succession. The fourth impulse causes the operation of relay 309 and the previously traced circuit is closed from battery "through the left hand winding of this relay over conductor 324 hence through the outer right back contact of relay 315, outer right front contact of relay 314, Winding of relay 315, outer left back contact of relay 316 to ground over conductor 325. Relay 315 operates and looks through its inner right contact and winding and the outer left back contact of relay 316 to the grounded conductor 325. Relay 315 opens the circuit of relay 314 and also the circuit through the left hand winding of relay 309. Relay 309 is then released. After an interval has expired, slow relay 307 releases and the circuit already traced is completed from ground over conductor 328 through the right front contacts of relays 408 and 416, right contact of relay 420, winding of relay 419 to battery. Relay 419 operates, extending the control leads from the counting relays through to the units register 403, and also closes a. circuit through its winding and inner upper contact thence over conductor 430 as hereinbefore traced through the winding of relay 305 to ground. Relay 305, however, being shunted does not operate at this time.

\Vith relay 419 and relay 315 operated, a circuit is completed from ground over conductors 326 and 325 through the outer left back contact of relay 312, inner left contact of relay 315, conductor 332, next to the inner lower contact of relay 419, winding of register relay 433 to battery. Relay 433 locks through it inner left contact to ground over conductors 434 and 321. Relay 433 closes a circuit from battery through the winding of relay 420, outer left contact of relay 433 to the grounded conductor 434. Relay 420 removes the shunt from the winding of relay 305 and this latter relay operates in series with relay 419. Relay 305 in the manner explained, causes the release of relay 306 which in turn causes the release of relays 305 and 419.

. sender connector 500 provided for this purpose and without waiting for the subscriber to send the remaining series of impulses. When therefore, relay 408 operates, it com pletes a circuit from battery through the winding of relay 310, conductor 333, outer left contact of relay 408, conductors 428 and 321 to ground at the left contact of relay 304. Relay 310 attracts its armature and closes a circuit over the grounded conductor 321, outer left back contact of relay 311, contact of relay 310, conductor 334, winding of re lay 509 to battery. Relay 509 operates and com )letes a circuit from round throu h t b the outer right back contact of relay 512, inner right front contact of relay 509, winding of relay 506 to battery. Relay 506 operates and locks over a circuit from ground, through middle right front contact of relay 509, outer right front contact of relay 506, winding of relay 512, left front contact of relay 506, second winding of relay 506 to battery. This latter circuit operates .relay 512 breaking the original energizing circuit for relay 506, and completes a circuit from ground at right front contact of relay 512, inner right front contact of relay 506, winding of magnet 503, to battery, operating magnet 503. The operation of relay 509 also completes a circuit from ground, right back contact of magnet 516, outer right front contact of relay 509, winding of relay 515, to battery, operating relay 515, which relay in turn closes a circuit from ground at its right front contact, winding of magnet 516, to battery. Magnet 516 operates and closes a locking circuit for itself through its left front contact to ground at right front contact of relay 512. It should be noted that relay 515 does not release until after magnet 516 locks.

The operation of magnets 503 and 516 extends the hundreds digit register leads to the hundreds digit relays in the marker and through these relays circuits are eX- tended to the frame connector 600 and trunk connector 650 associated With the particular portion of the sender connector operated by magnet 516. These particular marker connectors are assigned for the operation of the first step-by-step selector switch 200 in accordance with the settings of hundreds relay registers such as 400. The sender connector 500 may be so arranged that a number of similar marker equipments and corresponding circuits may be connected therewith but since such an arrangement does not form a part of this invention, nothing further need be said except that they may be associated through the sender connector by means of magnets similar to magnets 503 and 516.

It will be noted that the marker equipment shown in Figs. 5 and 6 connected to the relay register through the sender connector 500 will now be operated to cause the operation of the first selector switch in a step-by-step manner to pick out the desired outgoing group of trunks and an idle trunk in this group in accordance with the setting of the relay register 400. This operation will now be described. The operation of sender connector 500 completes a circuit for start relay 601. Relay 601 closes a circuit from ground over conductor 636, through device 500, conductor 590, right contact of relay 404, conductor 426, device 500, relay 520 to battery. Relay 520 is therefore the particular relay selected by the hundreds relay register 400 to initiate the operation of the first selector to select the first group of trunks and it should be understood that other register relays such as 405 and 406 etc. in operating would have caused the operation of the corresponding relays 521 and 522 etc. to initiate the operation of the first selector to select different groups of trunks depending on the hundreds digit selected by the subscriber. Relay 601 also completes a circuit from ground, through the right front contact of relay 601, conductor 636, outer back contact of relays 526, 522 and 521, and outer front contact of conductor 520, winding of relay 602, to battery. This operates relay 602 and initiates the operation of the frame connector 600 to pick out the first group of trunks and the trunk selector 650 to pick out the first idle trunk in the group selected. I

The operation of these two relays 601 and 602 completes a circuit from ground, left front contacts of relay 601, right front contact of relay 602, winding of relay 603, to battery. Relay 603 operates and completes a circuit from ground at right back contacts of relay 605, left front contacts of relay 603, one Winding of relay 604, to battery. Relay 604 operates and completes a circuit from ground at relay 601, inner right front contact of relay 603, outer right front con tact of relay 604, winding of relay 605, left front contact of relay 604 a second winding of relay 604 to battery. Relay 605 operates and completes a circuit from ground, right front contact of relay 605, inner right front contact of relay 604, winding of magnet 606, to battery. The operation of magnet 606 completes a circuit from ground at relay 601, outer right front contact of mag net 606, conductor 613, sender connector 500, conductor 519, inner left back contact of relay 311, conductor 340, sender connector 130, conductor 142, right back contact of relay 143, conductor 144, contact 212 of relay 208, winding of relay 205, to battery. Relay 205 operates and completes a circuit from ground, at left front contact of relay 205, conductor 210, magnet 612, to battery. Magnet 612 which is individual to the particular switch 200 shown operates and locks up over a circuit from ground at relay 601, inner right front contact of magnet 606, right front contact and winding of magnet 612 to battery. Frame connector 600 now operates and makes circuit connections to the first selector switch for operations under control of the first series of impulses.

When magnet 606 operates a circuit is also completed to initiate the operation of the trunk connector 650, from ground at relay 601, outer right front contact of magnet 606, inner left front contacts of relay 602, winding of relay 607, to battery. Relay 607 operates and completes a circuit from ground at right back contact of relay 609, left front contact of relay 607, one winding of relay 608, to battery. Relay 608 operates and completes a locking circuit for itself from ground at relay 601, inner right front contact of relay 607, outer right front contact of relay 608, winding of relay 609, left front contact of relay 608, and a second winding of relay 608, to battery. Relay 609 is operated by this circuit and completes a circuit from ground at right front contact of relay 609, inner right front contact of relay 608, Winding of magnet 610 to battery. Magnet 610 operates and completes a circuit from ground at relay 601, outer right front contact of relay 607, right front contact of magnet 610, outer right front contact of relay 603, outer left front contact of relay 602, winding of magnet 611, to battery. Magnet 611 operates and thus the operation of this magnet and magnet 610 operate the trunk connector 650 to connect the grou of trunks selected with their correspon ing trunk testing relays 660 to prepare these relays for the testing of the trunks in this particular group.

At the operation of the trunk connector 650 the circuit connections are established to operate a first selector switch 200 connectedthrough the frame conductor 600 as follows: Relay 613 is first operated from ground at relay .601, trunk connector 650, winding of relay 613, to battery. Relay 613 locks up over a circuit from ground, at relay 601, inner left front contact and winding of relay 613, to battery, and closes a circuit from ground at interrupter 614, right front contact of relay 613, conductor 615, winding of relay 616, to battery. Relay 616 operates and completes a circuit from ground at relay 601, winding of relay 617, left front contact and winding of relay 616, to battery. Relay 617 operates, when the interrupter opens, and locks up relay 616 and itself over the left front contact of relay 616 and also completes a circuit from ground at the interrupter 614 shown in Fig. 5, which it'is understood may be the same as the interrupter 614 shown in Fig. 6, through the inner right back contact of relay 530, conductor 531, outer left front contact of relay 617, conductor 61S, frame connector 600, conductor 619, inner right front contact of relay 205, winding of vertical magnet 206, to battery.

The interrupter 614 is now therefore connected through relay 617 to the vertical magnet 206 and in order to fully comprehend how the first impulse, that is the hundreds digit impulse, causes the operation of the vertical magnet 206, it is necessary at this point to describe how the testing relays 660 enter into the establishing of control circuits for this purpose. It will be remembered that relay 613 was operated at the moment the trunk connector 650 operated and the testing of an idle trunk in the selected group was then actually begun. It will be assumed that the third trunk is the first idle one in this first group of trunks and it should be mentioned here that one set of two relays are assigned to each trunk for this purpose; relays 620 and 621 to the first trunk, relays 622 and 623 to the second trunk and relays 624 and 625 to the third trunk, etc. Relays 620 and 622 are locked up due to this busy condition of the corresponding trunks as will hereinafter appear and the moment, therefore, that relay 613 is operated a circuitis established for relay 625 assigned to the third trunk as follows: ground at relay 601, outer left front contact of relay 613, left front contacts of relays 620 and 622, left back contact of relay 624, winding of relay 625, to battery. Relay 625 operates and completes a circuit previously prepared by the operation. of relay 617, as follows: ground at interrupter 614, Fig. 5, outer right back contact of relay 530, conductor 532, inher left front contact of relay 617, conductor 626, outer right front contact of relay 625, conductor 627, right back contact of counting relay 533, winding of counting relay 534, to battery. This circuit for counting relay 534, therefore, constitutes the controlling element by means of which the operation of magnet 206 is limited to but one step. As stated above when counting relay 534 operates on the first impulse from ground on the interrupter 614, it looks up over a circuit from ground at relay 601, conductor 629, winding of relay 533, left front contact and winding of relay 534, to battery. This circuit also operates and locks up relay 533 as soon as the connection to ground at interrupter 614 is broken. The operation of relay closes a circuit from ground at relay 601, conductor 629, left front contact of relay 533, winding of relay 530, to battery. lhe operation of relay 533 also opens the original energizing circuit for relay 534. The operation of relay 530 disconnects the interrupter 614 from the energizing circuit for relay 534 at its outer right back contacts. Thus it is seen that these two counting relays 534 and are permanently locked up over a ground from relay 601. Relay 530 also disconnects at its inner right back contact the interrupter 614 from the vertical magnet 206 which by this time has received but one impulse to advance the first selector to the first group of trunks aind control circuits will now be established to advance the first selector to the first idle trunk in this group.

Relay 530 now therefore connects the in terrupter 614 to control other counting relays and to establish a connection for the rotary magnet 207 as follows: from ground at interrupter 614, inner ri ht front contact of relay 530, conductor 535, frame connector 600, conductor 633, middle right front contact of relay 205, winding of rotary magnet 207, to battery, and a second circuit for the fourth set of counting relays as follows: ground at interrupter 614, outer right front contact of relay 530, conductor 536, inner right front contact of relay 625, conductor 634, right back contact of counting relay 537, winding of counting relay 538, to battery. The reason the fourth set of counting relays are selected is due to the idle condition of the third trunk as indicated by the operation of the test relay 625, and it should be observed that the first and second set of testing relays are provided with similar circuit connections for the control of the second and third set of counting relays. As stated above the first set of counting relays are permanently locked up and not available for control of the rotary magnet 207, which will now therefore, receive three impulses in succession from ground at interrupter 614, to bring the brushes of the selector on to the terminals of the third trunk. The first impulse received from the ground at interrupter 614 operates the rotary magnet 207 and counting relay 538. At the end of this impulse the rotary magnet 207 releases and counting relay 537 operates over a circuit from ground at relay 601, conductor 629, in ner left front contact of relay 530, counting relay 537, left front contact and winding of counting relay 538, to battery. These relays537 and 538 are thereby locked up. At the second and third impulse from ground at interrupter 614 the rotary magnet is operated to take two more steps and the counting relays 539, 540, 541 and 542 are operated and locked up in success on, as the circuit com-- pleted through the inner right front contact of relay 625 is extended over right front contacts of relays 537 and 540 in succession.

At the operation of counting relay 542, a circuit is completed from ground at relay 601, conductor 629, inner left front contact of relay 530, left front contact of relay 542, outer left front contact of relay 530, conductor 543, outer right front contact of relay 205, winding of relay 208, to battery. Relay 208 operates and connects the talking and test leads of the first selector 200 over the third set of terminals in the lirst group of trunks extending them to the connector switch 250. The operation of relay 208 also breaks the circuit for relay 205 at contact 212, which releases and breaks the connections for magnets 206 and 207. As relay 205- at its deenergization also breaks the above energizing circuit for relay 208, the operating times of these two relays are such that relay 208 will close a locking circuit for itself from ground at the front contact of relay 107, conductor 116, offnormal contact 213, lower armature, front contact and winding of relay 208, to battery before relay 205 breaks the original circuit.

As the marker equipment shown in Figs. 5 and 6 has now completed its function of controlling the first selector to connect with an idle trunk of the group determined by the hundreds digit it may be released and a similar marker equipment connected for the control of the connector 250 in accordance with the tens and units digit registered on the sender. The release of this marker equipment will now be described and it will be noted that circuits to initiate this releasehave already been prepared by vertical and rotary olfnorinal contacts 215 and 219 as follows: At the time the vertical magnet was first operated, a circuit was completed at right front contact of magnet 206, winding of relay 214, to battery. Relay 214, which is slow-torelease operates on the first operation of the vertical magnet and closes a circuit from ground, left front contact of relay 214, off-normal contact 215, conductor 216, winding of relay 144, to battery. Relay 144 operates and closes a locking circuit for itself from ground, at the front contact of relay 107, conductor 116, outer left front contact of relay 105, inner left front contact and winding of relay 144, to battery. \Vhen the rotary magnet is first operated a similar circuit is closed from ground, ri 'ht front contact of magnet 207, winding of relay 218, to battery. Relay 218 operates and closesa circuit from ground, left front contact of relay 218, and rotary off-normal contact 219, conductor 220, outer left front contact of relay 144, winding of relay 143, to battery. Relay 143 operates and closes a locking circuit for itself from ground, at the front contact of relay 107, conductor 116, outer left front contact of relay 105, left front contact, and winding of relay 143, to battery. At the final release of magnets 206 and 207, the original circuits for relays 214 and 218 are broken and when these relays release the original energizing circuits for relays 144 and 143 are broken so as to permit these latter relays to release at the proper time as will be hereinafter described. It will now be observed that at the seizing of the third trunk by the test terminal of the selector 200, a circuit is completed from ground, at front coir tact of relay 107, conductor 116, o'l'l normal contact 213, front contact 222 of relay 208, test brush 223, test terminal 229, conductor 225, contacts of trunk connector 650, left front contact of relay 625, winding of release relay 640, to battery. Relay 640 operates and closes a locking circuit for itself from ground at relay 601, left front contact and winding of relay 640, to battery. The operation of relay 640 closes a circuit from ground atrelay 601, right front contact of relay 6-40, conductor 641, sender connector 500, conductor 544, winding of relay 311, to battery. Relay 311 operates, closes a locking circuit for itself from ground on lead 321, outer right front contact and winding of relay 311, to battery, and breaks the original energizing circuit for relay 205 closed at the operating magnet 606, which circuit it will be observed has also been previously broken at contacts of relays 208 and 143. Relay 311 also breaks the circuit for relay 509 which permits the sender connector to release by the release in succession of relays 512 and 506 and magnets 503 and 516. The release of the sender connector 500 causes the release of relay 601 by the removing of ground at 523. Relay 601 in turn removes the ground from relays and magnets of the frame connector 600 causing them to release and also from relay 602, which relay in deenergizing permits the release of the relays and magnets of the trunk connector 650 in a manner similar to the release of the sender connector. The trunk test relays 613, 616 and 617 and the release relay 640 are then released.

It is now apparent how test relays 620 and 622 became operated to indicate the busy condition of the first two trunks at the time the trunk connector 650 was op crated. Observe that a ground potential is now present at test terminal 229 and a similar ground was at that time also present at test terminals 230 and 231 of the first and second trunk in this group. Circuits were therefore established for test relays 620 and 622 immediately upon the connection of conductors 232 and 233 through the trunk connector 650 and left back contacts of test relays 621 and 623, windings of relays 620 and 622 to battery. The relays 620 and 622, upon energizing establish locking circuits for themselves from ground at relay 601 and thus permit the test relay 625 to become energized through their left front contacts for the seizing of the third trunk.

As the sender connector and marker equipment are now released, the tens and units relay registers disconnected therefrom and the first selector switch connected to the trunk associated with connector switch 203, the next performance will be to operate this connector switch to select the called subscribers line in accordance with the settings of the tens and units relay registers 402 and 403. W'hile means to accomplish this result have not been shown in detail it is apparent that a marker equipment similar to the one shown could be employed. It will, therefore, be sufiicient to show how the association of such an equipment with the tens and units relay register may be initiated. When relay 420 of the unit relay registers energizes the following circuits are established: from ground at outer left front contact of relay 420, conductor 428, inner left back contact of relay 342, inner right front contact of relay 311, conductor 343, winding of relay 425, to battery. Relay 425 operates and completes a circuit from ground at front contact of relay 423, front contact of relay 425, conductor 439, outer right back contact of relay 342, conductor 344, selector 130, conductor 146, inner right front contact of relay 144, tip conductor 147, to the upper armature and front contact of relay 208, tip brush of selector 200, tip terminal of the third trunk leading to connector 250. Another circuit is established from ground, outer left front contact of relay 420, conductor 428, outer right back contact of relay 311, out over conductor 34:"). The first circuit may cause the operation. of a relay 290 similar to relay 205 in the circuit arrangement of connector 250 and the second circuit may cause the operation of a relay similar to relay 509 of sender connector 500 in a similar sender connector to initiate the association of the tens and units relay registers with such a sender connector and -i'narker equipment.

The release of the register sender at the end of the selection of the called subscribers line by this second sender connector and marker equipment will now be described. It may be initiated by the operation of relay 342 over a conductor 346 which may be connected to ground in a manner similar to the conductor 544 that caused the operation of relay 311. Relay 342 completes a circuit from ground at the outer left contact of relay 420, conductor 428, outer left front contact of relay 342, winding of relay 303, to battery. Relay 303 is energized and looks through its right contact to ground 'on conductor 322. Relay 303 at its left contacts, disconnects the impulse relay 301 and the balancing coil 302 from the calling subscribers line 101. Relay 301 releases and opens the circuit otslow relay 304. After an interval, relay 304 retracts its armatures and removes the ground from the holding conductors 322 and 321 whereupon all energized relays in the register sender and registers are permitted to release.

The removal of ground from holding conductor 322 may cause the release of the sender selector switch 130 in any suitable manner. The removal of ground from conductor 322 also causes the release of relay 105. Relay 105 disconnects the subscribers line from conductors 138 and 139 and extends said line through to the left windings of repeating coil 108 in the trunk 103. Relay 106 operates in serieswith the calling line and completes aholding circuit for slow relay 107 whereby ground potential is maintained on the sleeve conductor 116 to hold the connection. The release of relay 105 opens the holding circuit of relays 1 13 and 1&4. Relay 14: 1 on deenergizing, completes the tip and ring conductors of the trunk through to the first selector switch.

I In any well known and approved manner, ringing current may be applied to the calling subscribers line.

After conversation the subscribers replace their receivers on the switchhooks and relay 106 releases. After an interval, relay 107 becomes deenergized and withdraws ground potential from conductor 116, whereupon the holding circuits for the relay 208 of the first selector switch 200 and the correspond ing relay tor connector switch 203 are broken and the two switches are permitted to release the first selector by a circuit from ground, left back contact of relay 205,.back contact 226 of relay 208, oft-normal contact 227, winding of release magnet 228, to battery and the connector 203 in a similar manner. 1

As has been explained hereinbefore, the relay 602 is a group relay individual to the first group of trunks shown with selector switch 200. The relay 611 of the connecting device 650 is also a group relay individual tothis particular group of trunks. The re-/ lay 611 is wired to cause the operation of the relay 613 which identifies the first group of trunks in the switch 200 by causing the operation of relays-616 and 617. The connecting device 650 may have other relays similar to 611, one for each of the several groups of trunks outgoing from the switch 200. A second of these relays is indicated. These relays cause the operation of other group relays similar to the relay 613, and these latter relays in turn may cause the operation of other sets of relays similar to the set including relays 616 and 617.

While only three pairs of the testing relays are shownin the set 660, it will be understood that there may be as many of these sets as there are trunks outgoing from the selector switch 200. Assuming the usual basis of ten trunks per level in the switches of the type shown, the first chain or" relays of the testing relay set 660 applies to the first level. As above described, the primary movement is determined by conductors leading from the armatures ot' the several counting relays ot the set 510 through armatures of relays of the testing relay series 660. For the selection of the first group, which is the one assumed, the conductor 627 is shown leading to contacts of each of the ten relays 621, 623, 625, etc, pertaining to this first group of trunks and thence over conductor 626 throughcontacts of the group relay 617. For controlling the primary movement to select the second group of trunks, for example, the conductor which leads to the second set of counting relays in the-chain would extend through contacts of the second set of ten testing relays 660 in identically the same man ner and thence through contacts of relaysv similar to relay 617 to the conductor 532. Similarly, for other group selections other portions of the testing relay set 660 would be involved.

In a similar manner, the armatures of the several counting relays 510 are wired to con tacts of the testing relays 660 in the several groups for determining the secondary movement of the switch 200.

For a more detailed description of the manner in which connections may be extend ed through line switches and for the operation of the sender selectors, senders, and for the manner in which aplurality of markers are connected in succession to the senders to control successive switches, reference is made to the patent to S. B. Williams, No. 1,517 331, granted' December 2, 1924.

What is claimed is: v

1. In a telephone system, lines, a plurality of common senders for storing designations sent over said lines, progressively operable switches, a controlling mechanism common to said senders, means for connecting said mechanism with any one of the senders, and means under the direct control o1 said mechanism for directively operating said switches to extend said lines. v

2. In a telephone system, telephone lines, a plurality of common senders forreceiving and storing designations sent over said lines, progressively movable switches, a controlling mechanism common to said senders, means for connecting said mechanism with any sender, said sender arranged to transfer its designation to the controlling mechanism, and means controlled by said mechanism for directively moving said switches to extend said lines. I v

3. In a telephone system, lines, a plurality of common senders for storing designations sent over said lines, progressively movable switches, a switch controlling mechanism common to said senders and also common to said switches, and means under the direct control of said mechanism for directively operating any one of said switches to extend said lines.

4. In a telephone system, lines, a plurality of common senders for receiving and storing designations sent over said lines, progressively operable switches, a controlling mechanism common to said senders and also common to said switches, means for connecting said mechanism with an sender means for connecting said mechanism to one of said switches, and means controlled by said mechanism for directively advancing the switch.

5. In a tele hone system, telephone lines, a plurality 0 common senders for storing designations sent over called lines, a plurality of progressively movable switches com rising a switching stage, a controlling mar er common to said senders and common to said switches, means for connecting said marker with any of said senders, means for extending a calling line to one of said switches, means for connecting said marker to the particular switch to which said calling line is extended, and means under the control of said marker for operating said switch.

6. In a telephone system, a plurality of step-by-step' switches, a plurality of senders for storing designations, a controlling mechanism common to said senders, means for connecting said mechanism to any one of said senders, and for transferring the designation to such mechanism, and means controlled b said mechanism in accordance with the esignation stored in the sender for operating said step-by-step switches.

7 In a telephone system, lines, a plurality of common senders for receiving designations sent over said lines, a plurality of switches each arranged for a plurality of separate movements, a controlling mechanism common to said senders and common to said switches, means for connecting said mechanism with one of said senders, means for connecting said mechanism to one of said switches, and means for operating the switch to which suchv mechanism is connected in each of its movements.

8. In a telephone system, lines, a register Sender for storing designations sent over said lines, progressively operable switches, a controlling mechanism normally disassociated from said sender, means for connecting said mechanism to said sender, means for connecting said mechanism to one of said switches, and means controlled by said mechanism for directively operating said switches to extend said lines.

9. In a telephone system, subscribers lines, a register sender for receiving and storing designations transmitted over said lines, progressively operable switches, a

switch controlling marker normally disas sociated from said sender and from said switches, means for connecting said marker to said sender, means for connecting said marker to a desired one of said switches, and means under the direct control of said markor for selectively operating the particular switch to which said marker is connected for extending a subscribers line.-

10. In a telephone s stem, lines, a regis ter sender for storing esignations, progressively operable switches, a plurality of controlling mechanisms to whichsaid sender is common, means for connecting said send or to any one of said mechanisms, and means under the control of the connected mechanism for directively operating one of said switches to extend a line.

11. In a telephone system, telephone lines, a plurality of common senders for receiving and storin designations, progressively mov-- able switches, a plurality of controlling mechanisms common to said senders, means for connecting an idle mechanism to any one of said senders, means separate from the sender for connecting such mechanism to one of said switches, and means under the control of the connected mechanism for directively operating the switch to extend a telephone line.

12. In a telephone system, lines, a regis ter sender under the control of said lines for establishing designation records, pro essively operable switches, a switch contro ling marker, a multi-contact relay device for connecting said marker to said sender, a multicontact relay device for connecting said marker to one of said switches, and means controlled by the connected marker for dipectively operating the switch to extend a 13. In a telephone system, lines, a sender controlled over said lines for establishing designation records, a progressively operable switch, a group of trunks appearing in said switch, a switch controlling marker, means for connecting said marker to said sender, means for connecting said marker to said switch, said marker including a testing mechanism for performing a test of the trunks of said group, and means for directively opera-ting said switch to extend a line over an idle trunk as determined by the test. s

14. In a telephone system, lines, a register sender for storing designations sent over said lines, a progressively operable switch, a plurality of groups of trunks appearing in said switch, a switch controlling marker, means for connecting the marker to said sender, separate means for selectively connecting the marker to one of said groups of trunks, said marker including a testin mechanism for performing a test of al trunks in the selected group to determine an idle one, and means controlled by the trunk group in any of said switches, said marker for directing said switch to an idle marker including a series of testing relays trunk. for performing a test of said trunks, and

15. In a telephone system, lines, a pluralmeans controlled by the marker for direc- 5 ity of senders for storing designations, protively operating said switches to make con- 15 gressively operable switches, groups of nection with an idle trunk. trunks appearing in said switches, a plural- In witness whereof, I hereunto subscribe ity of switch controlling markers, means for my name this 27th day of September, A. D. connecting any marker to any sender, m'eans 1923.

10 for connecting the connected marker to any l/VARREN W. CARPENTER. 

